1. Field of the Invention
The present invention relates to scratch-resistant, impact-resistant polycarbonate (PC) compositions and moulding compositions which have good mechanical properties as well as high resistance to chemicals, to a process for their preparation, and to their use in the production of moulded articles, in particular of casings for flat screen devices.
2. Description of Related Art
JP-A 05-070653 describes hollow glass spheres having high compressive strength as an additive in maleimide-modified ABS moulding compositions. The moulding compositions have a reduced density, a high flexural modulus and good heat distortion resistance. Advantageous effects on joint line strength, resistance to chemicals or increased scratch resistance are not reported.
EP-A 391 413 describes the use of talc as a filler in impact-modified polycarbonate. An influence on the scratch resistance or processing behaviour is not described. Positive effects of this additive on notched impact strength or joint line strength are not described.
JP-A 01-104637 describes mixtures of crystalline polypropylene and modified polypropylene, to which hollow particles of Al2O3-SiO2 have been added. Compared with a corresponding mixture with talc, improved scratch resistance with a reduced flexural modulus was obtained by means of these particles. Effects on the joint line strength or the resistance to chemicals by the addition of the aluminosilicate particles are not described.
JP 2003-326623 describes multi-layer sheets of polycarbonate in which an intermediate layer for insulation against heat and sound is provided with hollow ceramics spheres. However, the spheres are not present in a blend with polycarbonate and other polymers such as, for example, ABS.
EP 2087478 A1 describes impact-modified filled polycarbonate compositions having increased demands in terms of mechanical properties and improved flow behaviour, which compositions are obtained by addition of hollow ceramics spheres. An influence of these additives on the impact strength and/or joint line strength is not described, however.
US 20080103267A1 describes mixtures of polycarbonate, small amounts of an SAN copolymer and specific polyorganosiloxane/silica preparations for transparent moulding compositions. However, these compositions do not contain impact modifiers, for which reason the impact strength and joint line strength of these compositions are inadequate.